1. Technical Field
The present disclosure relates to an organic electroluminescence element (hereinafter abbreviated to “organic EL element”), which is an electric light-emitting element.
2. Description of the Related Art
An organic EL element has a multilayer body including an anode, a cathode, and an organic layer located therebetween and having a light-emitting layer. In general, the multilayer body is provided on a substrate, such as a glass board, and covered with a sealant. Outside the region covered with the sealant, there are anode lead-out and cathode lead-out sections electrically coupled to the anode and the cathode, respectively. Through these lead-out sections, voltage provided from an external power supply is applied between the electrodes. The organic EL element is driven using the phenomenon called electroluminescence, which occurs through the recombination of a hole and an electron injected from the anode and the cathode, respectively, into the organic layer upon the application of voltage between the electrodes.
In recent years, the use of a substrate having an electroconductive surface for organic EL elements has been proposed. Examples of substrates having an electroconductive surface include metallic foils, plastic films coated with a metallic film or any other electroconductive film, and glass boards coated with an electroconductive film. In particular, the use of a flexible substrate, such as a metallic foil or a plastic film coated with a metallic film, provides an organic EL element that is flexible and can be rolled and bent (hereinafter referred to as a “flexible organic EL element”). A flexible organic EL element can be produced using, for example, roll-to-roll processing.
The structure of an organic EL element having a substrate with an electroconductive surface is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2012-174558. In the organic EL element disclosed in this publication, the electroconductive surface of the substrate is used as the cathode and the cathode lead-out section.
FIG. 8 is a cross-sectional diagram illustrating the organic EL device disclosed in this publication. The organic EL device has a first substrate 2 capable of serving as a cathode layer, an organic layer 3 on the first substrate 2, an anode layer 4 (41 and 42) on the organic layer 3, and a second substrate 6 bonded to the anode layer 4 via an adhesive layer 5. The first substrate 2 and the anode layer 4 extend to the outside of the region where the organic layer 3 is present, and part of the extended portions of the first substrate 2 and the anode layer 4 expose from under the second substrate 6 to form a cathode lead-out section 40b and an anode lead-out section 40a, respectively. An insulating layer 7 insulates between the extended portions of the first substrate 2 and the anode layer 4.